New 41-250 - Printable Version
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New 41-250 - dberman51 - 02-19-2010 04:28 AM
I went to the Radio XLI show in Westford, MA last Sunday and a nice 41-250 followed me home. I bought it from the fellow who restored it, who described it as "8 tubes, works well." I tested it in the car in the parking lot before leaving the show, and it did work, running on an inverter.
This is my first Philco (most of my other radios are GE), and is the first radio I have ever bought restored by someone else. I checked it out thoroughly. It had been completely re-capped, done very nicely by unsoldering the old ones, although I re-did the electrolytics and the line bypass caps, moving them to their original locations. There had been only one bakelite condenser, originally holding the two line bypasses, and from the looks of the tar residue it seems that the departure of the bakelite condenser may have been dramatic. I cleaned off the tar and cleaned up quite a few solder splashes and other residue left behind from the re-capping. I measured a few voltages and they were right on.
The rubber insulated wiring is still there, but amazingly enough it is still in excellent condition, soft and flexible with no cracks. He had replaced the power cord, and had done a nice job fabricating a small aluminum bracket attached to the rear of the push-button assembly with spacers, to hold a new push-on/push-off power switch to replace the old one while preserving the original operation.
The escutcheon is clearly one of the new reproductions.
All put back together, the set works really well. Highly sensitive including on shortwave, and it really surprised me with its excellent sound quality. It is about the nicest sounding set I have except for the full-on hi-fi/stereo system.
Note from site admin: Sorry, but the photos which were attached to this post are no longer available.
Now I have some questions for the Philco experts:
1) Are these the correct knobs for this set? The photos I have seen on radio attic and elsewhere show plastic knobs which match the escutcheon. These knobs are wood.
2) There are no label tabs for the push-buttons, not even Off-On or Television, and I don't see any way to put any tabs in. There is a single transparent plastic strip behind the tab windows which seals off the space. How to insert the tabs? Are they being reproduced or do I have to make them myself?
3) I have never seen this funky output circuit. It seems to be a push-pull output stage but with no phase inverter or interstage transformer. If I understand the schematic correctly they seem to be using the top output tube as a phase inverter, using the screen grid as a second plate, which they then couple to the grid of the bottom output tube. I would never have thought this would work but it sounds excellent. I notice that they use this circuit in the 8 and 9 tube consoles also, but the 10 tube consoles get a real phase inverter. DId I understand this circuit correctly?
4) The schematic (which also applies to the 41-255) shows separate indicator lamps for the different bands, switched by the band-switch. This set has only one lamp in that position, in a pivoting lampholder operated by a second dial cord driven by the band-switch shaft. The set-up is clearly original. Was this a running change or was the schematic always incorrect for this model? Both the schematic and the set indicate Code 121.
That all for now, I'm sure I'll have more questions later. Thanks!
Re: New 41-250 - Ron Ramirez - 02-19-2010 02:35 PM
Hello and welcome!
dberman51 Wrote:1) Are these the correct knobs for this set? The photos I have seen on radio attic and elsewhere show plastic knobs which match the escutcheon. These knobs are wood.
No, those are not the correct knobs. The correct knobs are plastic; the originals were Tenite as were the original escutcheons, and they, too, shrink, warp and disintegrate over time. Correct repros may be purchased from the same person who made the repro escutcheon for your set: Larry Bordonaro at Old-Time Replications.
dberman51 Wrote:2) There are no label tabs for the push-buttons, not even Off-On or Television, and I don't see any way to put any tabs in. There is a single transparent plastic strip behind the tab windows which seals off the space. How to insert the tabs? Are they being reproduced or do I have to make them myself?
Unless you are lucky enough to purchase one of the original call letter tab kits sometimes sold on eBay, you will have to make your own. They aren't hard to do on any computer.
dberman51 Wrote:3) I have never seen this funky output circuit. It seems to be a push-pull output stage but with no phase inverter or interstage transformer. If I understand the schematic correctly they seem to be using the top output tube as a phase inverter, using the screen grid as a second plate, which they then couple to the grid of the bottom output tube. I would never have thought this would work but it sounds excellent. I notice that they use this circuit in the 8 and 9 tube consoles also, but the 10 tube consoles get a real phase inverter. Did I understand this circuit correctly?
Yes, you do. One of Philco's ways of pinching pennies, they came up with that idea for some of their 1937 models and used it a lot later on on sets such as yours.
dberman51 Wrote:4) The schematic (which also applies to the 41-255) shows separate indicator lamps for the different bands, switched by the band-switch. This set has only one lamp in that position, in a pivoting lampholder operated by a second dial cord driven by the band-switch shaft. The set-up is clearly original. Was this a running change or was the schematic always incorrect for this model? Both the schematic and the set indicate Code 121.
It was a running change, another way for them to pinch pennies - use one dial lamp as the band indicator instead of individual lamps for each band. The individual lamp idea works better - you don't have the problems of mechanical misalignment - but, of course, three bulbs cost more than one.
Re: New 41-250 - radiorich - 02-20-2010 07:07 AM
Even if that set does not have the correct knobs it still is a great looking set that you picked up.
Re: New 41-250 - Arran - 03-02-2010 05:01 AM
The Philco manuals describe that funky output circuit as "Screen grid inversion" they do work slightly better for fidelity then a single ended tube but the power output is only marginally more, good enough for a table model in any case. If you look at the schematics for the similar sets with a phase inverter tube the power output is higher, some say the fidelity is better too, but I think that the B+ voltage is higher too.
Everyone is right about the knobs though, those wooden knobs belong with an older radio likely from the early to mid 1930s. The original style knobs were made out of a grainy coloured plastic like the escutcheon with a triangle molded on the face, Larry Bordanaro makes reproductions but his may have a set screw which the originals did not have.
Re: New 41-250 - dberman51 - 03-02-2010 08:55 PM
I've already gotten the correct reproduction knobs (push-on type) from Radio Daze and the set looks much better. I also found and replaced a couple of really weak tubes and the set works better now, too.
Is there an issue with the reproduction escutcheon that makes it difficult to insert tabs? I thought I saw something on ARF about the supplier changing the mould.
Thanks for the information about the funky "screen inversion" circuit. Looking at the component values, it really shouldn't reduce output power significantly, but it should increase the amount of harmonic distortion compared to a conventional push-pull output stage. So the set should sound as loud as if it had a phase inverter, but not as clean. I don't think you could compare power output between screen inversion and phase inverter sets if the B+ changed also, because B+ is the most significant determinant of power output given similar output tubes.
Re: New 41-250 - Ron Ramirez - 03-02-2010 09:09 PM
dberman51 Wrote:Is there an issue with the reproduction escutcheon that makes it difficult to insert tabs? I thought I saw something on ARF about the supplier changing the mold.
You may have read the discussion of that subject here.
Call letter tabs aside, Larry's repro escutcheons are the only available reproductions, and they look excellent, maybe even better than new?
Larry is, most likely, Radio Daze's supplier. I am not aware of anyone else making these escutcheons.
Re: New 41-250 - dberman51 - 03-03-2010 04:00 AM
Thanks so much for the reply and for the link to the thread about the escutcheon. I saw an escutcheon for a 1942 set that had slots above the tab windows to slide the tabs into. My escutcheon doesn't have those slots. How were the tabs loaded into an original 1941 escutcheon? Just pop them in from the front and then pop in a plastic cover over them?
Re: New 41-250 - gary rabbitt - 03-06-2010 07:16 AM
The clear covers where the station tabs go, can possibly be removed from the frontside. Small call tabs are inserted, then the clear cover is placed back.
I remember hearing about the repro tab holders, and someone enlarged them to make the tabs fit. I think I remember hearing that the mold was also redone to fix that.
Anyway, here are two sheets that I have scanned, they are genuine Philco call tab sheets.
Save them at this resolution to preserve detail. When you print them out, you can adjust the print size to make then correct.
If there is a station that you need, and it is not on the sheet, simpley 'edit' and borrow letters from other labels to make your own station. (Copy/paste letters together.)
Re: New 41-250 - dberman51 - 03-06-2010 03:50 PM
Thanks Gary, those look great.
Re: New 41-250 - Michael Dennis - 03-07-2010 04:42 PM
I have the 41-255 I purchased back on June 4th. 2008. I bought it for $25 at a local antique shop. I'd been inactive in the hobby for about 30 years and this was the 1st. radio I purchased since my reawakening. All in all it's in pretty good condition unrestored. Haven't gotten to it yet. Probably the best bargain I've found, along with a 1939 model Zenith 7-S-363 I found last November, (I know, Ron, you're not too keen on Zeniths. Please forgive my waywardness!) I really like the look of the '250 and '255. From all that I've heard they sound great too.
Best regards, Mike
Re: New 41-250 - Ron Ramirez - 03-07-2010 06:14 PM
Mikhail7 Wrote:(I know, Ron, you're not too keen on Zeniths. ...)
To be honest, I probably wouldn't mind owning a Zenith or two, but I do not wish to pay those outrageous prices for a radio with a big black dial.
I do have one Atwater Kent in my collection, a model 20 "big box" with a model L horn - the horn has no driver or cup which held the driver in place.
Re: New 41-250 - Michael Dennis - 03-07-2010 07:19 PM
I know what you mean about the big money for the black dial Zeniths. The 7-S-363 was a relative bargain at $75. All the pushbuttons and tabs that are usually broken or missing are present and intact. Cabinet not too bad, chassis pretty clean, speaker ditto. I've seen ones in far worse shape for more money. Incredible but there's a local guy with a restored 8-S-463 for $895! That's $45 more than a restored 12-S-265, to me a far more desireable radio, I know of, also, somewhat locally. I like a few Atwater Kents myself too. But Philcos and Zeniths are my all time favorites. My dad's old 42-1008 console sounded superb.
Thanks, Ron, for keeping Philco Phorum for us radio addicts. I'm glad the bench and this site are back up. I think this is a friendlier site than that alternative place. It seems that if you're not a big name reputation restoration guy or are not a member of some of the "cliques" over there, everyone except a newbie gets largely ignored. I feel that way anyhow. I don't feel neglected here at all. I hope your college studies go well. I'm finally working now after 1.5 years of being unemployed. The world looks a lot better to me now!
Re: New 41-250 - Arran - 03-08-2010 06:59 AM
Ron Ramirez Wrote:Mikhail7 Wrote:(I know, Ron, you're not too keen on Zeniths. ...)
I filled my need for sets with a big, black airplane dial 20 years ago, I bought a Stewart Warner, and unlike the Zenith dials this one is made out of painted glass.
There were some other makes that had nice big black dials of course, Admiral (Continental Radio and Television), and Sparton also had some black dial sets that are a lot less expensive then Zenith.
Re: New 41-250 - Michael Dennis - 03-08-2010 01:55 PM
I don't think I've ever been close to a Stewrt Warner with a black dial. But what got me intetrested in old radios in the 1st. place was my dad's Philco 42-1008. Then, almost two years ago I saw this 41-255 at an antique store that's a three minute walk from where I live and I thought, "Hey, that sliderule dial reminds me of dad's old Philco." It was priced at $35 but I talked the man down to $25. I still would've paid $35 for it. Beautiful set, and if it sounded even close to the '1008, well... But I've come to appreciate earlier sets as well. I apologize, guys, I didn't mean to hijack or derail this thread about the '250. That and the '255 are really attractive units, and I bet they're great performers too.
Re: New 41-250 - Ron Ramirez - 03-08-2010 05:17 PM
The 41-250 and 41-255 are great performers...but they are a major PITA to restore. I've owned both. I currently have another 41-250, but I am in no hurry to restore it as I dread tackling those rubber-covered wires around the bandswitch.